1. Field of the Invention
The present invention relates to a hybrid-type watercraft propulsion system having an engine and an electric motor as a source of driving force for a propeller.
2. Description of Related Art
Japanese Publication No. JP-A-2004-257294 discloses a technique of assisting the driving power of an engine by the driving power of an electric motor for driving a power transmission device. However, this document is directed to engine operation consistency with electric motor operation on the assumption that the engine is always running when underway.
Japanese Publication No. JP-A-2006-36086, teaches a throttle grip that can be operated in a freely rotatable manner provided on a bar handle, and a control switch provided in the vicinity of the throttle grip. By operating the control switch, running and shut off of the engine and the electric motor, as well as the rotational direction of the electric motor can be controlled, and the rotational speeds of the electric motor and engine can be adjusted according to the turning operation of the throttle grip.
However, since both the control switch and the throttle grip must be used to control the running, shut off, and rotational speeds of the engine as well as the electric motor, the operation of such control means was troublesome.